Frozen vegetables produced in most areas of our country do not get the desired effect. They seem to be beaten by frost. Once they are thawed, they will brown, become soft and rotten, and lose their umami taste and carry peculiar smell when eaten. The reason for this change is that It is because vegetables contain various enzymes. Although some manufacturers blanch the vegetables before freezing to inactivate the enzyme activity, the effect is not satisfactory. This is because the raw materials are different and the types of enzymes contained are also different. Even if it is the same raw material, the types, quantities, and activities of enzymes contained in different growth periods or different organ stages in the same growth period are different. Different enzymes have different thermal tolerance. Therefore, it is necessary to In order to improve the quality of quick-frozen vegetables, in addition to mastering the appropriate blanching degree according to different situations, understand the types and quantities of enzymes contained in quick-frozen raw materials and the changing laws of enzyme activities in different growth periods, and then master the best harvest period , It is very important to obtain high-quality raw materials and improve the quality of quick-frozen products, but domestic and foreign research in this area is almost blank.